@paulread2922 As those monitors have been stored in damp conditions you might consider 'warming' the line output transformer to drive out any moisture that's been absorbed over the years. On valve sets the symptoms of moisture are reducing width after 30-45 mins of operation and the transformer running hotter than it should, effect is almost like a shorted turn. Passing a small current through the transformer for 24 hours or so drives the moisture out. On valve sets it's easy, connect between line output anode valve top cap and EHT rectifier cathode, you want about 1 to 2 watts which your bench supply will do.Transformer should feel just slightly warm to the touch when the current is passing through it. More awkward with transistors as they may need disconnecting.Anyway,just a thought.
And "ola" to all our viewers in Portugal. Do go and visit the RTP museum if you are ever in Lisbon. They have an excellent display and English speaking curator.
dear God im a cameramen ( joined in 1990 ) and all i have to do is point glass at stuff, tho i can remember when we had people employed who could actually understand this video and follow circuit diagrams, not its all IT people
Well done, thank you.
Horizontal intermittent faults are always fun to chase.
I worked on final test of these in the Pye factory in the 60's. They are very nice and simple inside.
I am amazed that we got 4 out of 5 up and running from such an unpromising start. They were so well built.
Those red capacitors are notorious for problems, think they were made by Plessey.
Are they dual standard 405/625 monitors?
So we found! These monitors will also do 525/60. Truly multi-standard.
@paulread2922 As those monitors have been stored in damp conditions you might consider 'warming' the line output transformer to drive out any moisture that's been absorbed over the years. On valve sets the symptoms of moisture are reducing width after 30-45 mins of operation and the transformer running hotter than it should, effect is almost like a shorted turn.
Passing a small current through the transformer for 24 hours or so drives the moisture out. On valve sets it's easy, connect between line output anode valve top cap and EHT rectifier cathode, you want about 1 to 2 watts which your bench supply will do.Transformer should feel just slightly warm to the touch when the current is passing through it.
More awkward with transistors as they may need disconnecting.Anyway,just a thought.
Good tip, Hugh
And "ola" to all our viewers in Portugal. Do go and visit the RTP museum if you are ever in Lisbon. They have an excellent display and English speaking curator.
@paulread2922 Boa Tarde!
They have a virtual museum online which I've seen. In the very early days RTP used to supply TV's to viewers as well.
dear God im a cameramen ( joined in 1990 ) and all i have to do is point glass at stuff, tho i can remember when we had people employed who could actually understand this video and follow circuit diagrams, not its all IT people